1. Field of the Invention
The present invention relates to an apparatus and process for separating isotopes. More particularly, it relates to an apparatus and process for separating isotopes using a plurality of developing units connected to at least one liquid-supply main pipe.
2. Description of the Prior Art
In separating and concentrating an isotope from a mixture of isotopes on an industrial scale, a desired amount of separation and concentration thereof is generally obtained by combining a large number of separation units in the form of a network called a "cascade" since the separation factor of a single isotope separator is usually very small. For example, Kunio Higashi; Uranium Concentration (published by Nikkan Kogyo Shinbun Sha in 1971) teaches that in the case of producing 5% concentrated uranium-235 using natural uranium as the raw material by a gaseous diffusion method, it is necessary to form a cascade by combining, in series, separation units composed of 902 concentration stages and 500 recovery stages. Also, in the case of producing the uranium isotope on an industrial scale by gas centrifuging, it is necessary to form a cascade by combining, both in series and in parallel, several hundred thousands of centrifuges per plant and the entire separation apparatus used for this purpose is complicated and hard to control.
For example, either the cascade of 1400 stages in the gaseous diffusion unit or the cascade of several hundred thousand centrifuges acts as one separation apparatus where the stream of uranium hexafluoride gas in each stage must be accurately controlled in order to maximize the separation factor of the uranium isotope. Furthermore, if a part of a large number of the separation units shuts down, the resulting disturbance of the gas stream or the concentration of isotopes would extend all through the cascade. For recovering under the optimum separation conditions, complicated calculations and operation control may be required. Still further, in order to slightly change the uranium isotope concentration of a product by the operation, the concentration must be changed by controlling the operation conditions of each of the many separation units while trying to maximize the separation factor of the cascade.
In separating an isotope on an industrial scale, it has been a common observation that several thousands to several hundred thousand separation units must be assembled into one cascade, which causes various difficulties in operation.